JP2006184195A - On-site monitoring device of air-drive valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-site monitoring device of an air-drive valve that can be surely recorded and stored, if operation data exceeding a normal state occurs by automatically monitoring data during operation of the air-drive valve by low power consumption. <P>SOLUTION: The air-drive valve 1 for driving a stem 18 fixed on a diaphragm 21, by introducing compression air in a pressure chamber 23 includes a sensor 34 for detecting the operation data of the valve attached to a valve structure member, and a monitoring means 33 for intermittently monitoring output of the sensor 34, and a recording means 32 for recording output of the sensor 34. The recording means for recording output of the sensor 34, if the output of the sensor 34 has a predetermined trigger value to exceed prescribed number-of-times in a prescribed period. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an on-site monitoring device for an air driven valve that is installed in a power plant or the like and controls various fluids.

  In plants such as nuclear power plants and thermal power plants, many large and small valves are installed. And in order to drive these valves, the drive device which uses electricity or compressed air as a power source is used. Here, the electrically driven valve is used for a relatively large valve, and the air driven valve is used for a relatively small valve. In addition, air driven valves are often used as control valves with a positioner. When used as a control valve, the drive frequency is naturally higher than that of a normal application. However, even when not used as a control valve, an air-driven valve is generally compared with an electric drive valve. The driving frequency tends to be high.

Conventionally, as a means for ensuring the reliability of such an air-driven valve, a method of collecting operation data of the air-driven valve while traveling around the site has been employed (see, for example, Patent Document 1). Further, although not related to the air drive valve, as a technique for recording the operation data of the local device, a remote monitoring control device is disclosed in which a trigger value is set and data is recorded when the trigger value is exceeded. (For example, refer to Patent Document 2). Furthermore, a long-time recording apparatus that consumes less power and can record sudden phenomena such as earthquakes over a long period of time has been disclosed (for example, see Patent Document 3).
JP-A-5-28391 JP-A-6-327170 JP-A-8-247797

  However, in the method of collecting operation data by visiting the site, the burden is not great if the number of valves installed is small, but the human burden increases if the number of valves installed is large. In addition, the method of collecting operation data by visiting the site has a problem that the event occurring on the site cannot be reliably grasped depending on the frequency of the tour.

  Here, the controlled object of the air driven valve is mainly liquid or gas. In many cases, the condition of the liquid or gas to be controlled is constantly changing. For example, if the controlled object is water vapor, the temperature, pressure, and flow rate of the water vapor change, and if it is constant, it is rather small. In addition, it is inevitable that the compressed air pressure, which is the power source of the air driven valve, also fluctuates. In such a case, even if the air drive valve fails, it cannot be easily determined whether the cause is in the controlled fluid side of the valve or in the control system. There is a problem that a great deal of time must be spent investigating the cause of the failure.

  In addition, there may be a method of constantly monitoring the operation data, but unlike the electrically driven valve, the air driven valve often has no power supply nearby, and it may be difficult to secure a power supply for driving the monitoring device. Not a few. Therefore, when a monitoring device is provided, it is necessary to use a battery-driven monitoring device, but there is a problem that power consumption must be reduced as much as possible in order to perform long-term state monitoring with the battery-driven monitoring device.

  Accordingly, the invention according to the present application provides an on-site monitoring device for an air-driven valve that automatically monitors data during operation of the air-driven valve with low power consumption and can reliably record and store operation data that exceeds a steady state. This is the issue.

  According to a first aspect of the present invention, there is provided an air drive valve for driving a stem fixed to a diaphragm by introducing compressed air into a pressure chamber, and a sensor for detecting operation data of the air drive valve attached to the valve structure member; And a monitoring means for intermittently monitoring the output of the sensor and a recording means for recording the output of the sensor, and when the output of the sensor exceeds a predetermined trigger value within a predetermined period, The output of the sensor is recorded.

  According to a second aspect of the present invention, there is provided an air drive valve for driving a stem fixed to a diaphragm by introducing compressed air into a pressure chamber, and a sensor for detecting operation data of the air drive valve attached to the valve structure member; And a monitoring means for intermittently monitoring the output of the sensor and a recording means for recording the output of the sensor, and when the output of the sensor exceeds a predetermined trigger value within a predetermined period, The trigger value is shifted, and the output of the sensor is recorded when the output of the sensor exceeds the trigger value after the shift a predetermined number of times.

  According to a third aspect of the present invention, there is provided an air drive valve for driving a stem fixed to a diaphragm by introducing compressed air into a pressure chamber, and a sensor for detecting operation data of the air drive valve attached to the valve structure member; And monitoring means for intermittently monitoring the output of the sensor and recording means for recording the output of the sensor, and monitoring if the output of the sensor exceeds a predetermined trigger value within a predetermined period. The interval is shortened, and the output of the sensor is recorded when the output of the sensor exceeds the trigger value within the predetermined period within the predetermined number of times.

  According to a fourth aspect of the present invention, in the on-site monitoring device for an air-driven valve according to any one of the first to third aspects, the sensor is a strain gauge attached to a yoke of the air-driven valve. To do.

  According to the on-site monitoring device for an air driven valve according to the first aspect, since abnormal data can be detected and recorded before a failure occurs in the air driven valve, the failure can be prevented beforehand. Also, by analyzing the abnormal data, the cause of the failure can be easily clarified. Furthermore, since the operation data is intermittently monitored, the power consumption as the monitoring device is reduced, and it is possible to monitor the battery for a long time.

  According to the on-site monitoring device for an air driven valve according to claim 2, the trigger level is automatically shifted while continuing the operation of the air driven valve even if the operation data of the air driven valve exceeds a predetermined trigger value. Therefore, by setting the trigger value to a low value at the beginning, it is possible to grasp the change with time of the operation data.

  According to the on-site monitoring device for an air-driven valve according to claim 3, since the output of the sensor exceeds a predetermined trigger value within a predetermined period, the monitoring interval for intermittent monitoring can be shortened and monitored. The probability of capturing abnormal data is improved. In addition, detailed monitoring can be performed in accordance with the operating conditions of the air driven valve.

  According to the on-site monitoring device for an air driven valve according to the fourth aspect, it is possible to monitor abnormality of the thrust value acting on the stem.

  Embodiments of the present invention will be described below with reference to the drawings. First, the configuration and operation of an air driven valve to which the present invention is applied will be described. FIG. 1 is a longitudinal sectional view showing a configuration of an air driven valve to which the present invention is applied. In the illustrated air drive valve, a valve positioner is provided as a control valve for performing flow rate control. However, the valve positioner is not required for applications that do not require a function as a control valve.

  A top guide type single seat type air driven valve 1 shown in FIG. 1 has a main body part 2 for controlling the flow rate of a controlled fluid 9 such as water or water vapor, and a valve plug 3 is reciprocated in the axial direction of the main body part 2. A diaphragm type operation unit 4 is provided, and a valve positioner 5 for adjusting the valve opening degree according to the input signal I is added. The main body 2 is configured such that the controlled fluid 9 in the upstream passage 10 of the pipeline passes through the opening 11a provided in the central portion of the partition wall 11 and exits to the downstream passage 13 of the pipeline. Yes. A seat ring 12 is fitted in the center of the partition wall 11. Then, when the valve plug 3 moves up and down along the guide ring 14, the opening degree of the opening 11a is changed, and the flow rate of the controlled fluid 9 is controlled. The upper rod 3a of the valve plug 3 is slidably inserted into the plug insertion hole 16 of the upper lid 15 via the gland packing 17, and the upper end of the rod 3a is connected via the stem 18 and the stem connector 19 of the operation unit 4. It is connected. The stem 18 is urged downward by a spring 20 and its upper end is fixed to a diaphragm 21 and moves up and down according to the pressure in the pressure chamber 23 of the diaphragm case 22. When the internal pressure of the pressure chamber 23 increases, the stem 18 is lifted upward, the valve plug 3 connected via the stem connector 19 is also moved upward, and the valve opening degree of the opening 11a provided in the main body 2 is increased. growing. Conversely, when the internal pressure of the pressure chamber 23 decreases, the valve plug 3 moves downward and the valve opening decreases.

  In the control valve including the valve positioner 5, the pressure of the pressure chamber 23 is adjusted by the valve positioner 5. The valve positioner 5 receives a signal indicating the valve opening from the input terminal 7, detects the valve opening by a lever 24 that rotates as the stem 18 moves up and down, and feeds back the value to the actual valve opening. The pressure of the pressure chamber of the operation unit 4, that is, the air chamber 23 is adjusted so as to match the valve opening degree indicated by the input signal. In such a control valve, the operation unit 4 includes a stem 18 and a spring case 25 fixed to the main body upper lid 15, a spring 20 disposed in the spring case 25 and biasing the stem 18 downward, and a spring case 25. The diaphragm case 22 is arranged on the top, and the diaphragm 21 is arranged with its peripheral edge held in the diaphragm case 22, and the upper end of the stem 18 is connected to the diaphragm 21. In addition, a guide bushing 26 is provided at the connecting portion between the diaphragm case 22 and the spring case 25. The guide bush 26 is inserted through the stem 18 with an O-ring 27 interposed in order to maintain the sealing performance of the air chamber 23. The gasket 28 is attached to the. Reference numeral 29 denotes a pipe as an air supply path for supplying the air pressure output from the valve positioner 5 to the air chamber 23. The valve positioner 5 includes an input circuit, a control arithmetic unit, an air pressure generator, a valve displacement detector (not shown), and the like, and the valve opening of the control valve is a target value that is a target value given as an input signal I. Always follow the valve opening. Among these, the input circuit can input an input signal I given in the form of a current value from the input terminal 7 through two transmission lines from a controller (not shown) to a control arithmetic unit built in the valve positioner 5. A circuit power supply for the valve positioner 5 is also created while converting to a voltage value. On the other hand, a valve displacement detector (not shown) is composed of a potentiometer, a rotary encoder, or the like, detects the valve opening from the rotation angle of the lever 24 that changes with the valve lift, and uses this as an electrical signal. And output to the control calculator as the measurement valve opening. The control arithmetic unit compares the target valve opening from this input device with the measured valve opening from the valve lift detector linked to the lever 24, and the air pressure generator so that these deviations approach zero. Output air pressure control signal. Further, the air pressure generator controls the pressure in the air chamber 23 through the pipe 29 by increasing, decreasing or holding the output air pressure based on the air pressure control signal from the control arithmetic unit.

  Here, in the air-driven valve 1 as described above, the load acting on the stem 18, that is, the thrust of the stem 18 is fluid pressure, seat pressure, sliding resistance of the gland packing 17, sliding resistance of the guide ring 14, etc. Affected by. At intermediate openings other than full opening and full closing of the valve, the sliding resistance of the gland packing 17 and the sliding resistance of the guide ring 14 are the main factors affecting the thrust of the stem 18. However, the following events may occur in the air-driven valve 1 as described above. For example, impurities contained in the controlled fluid 9 enter between the valve plug 3 and the guide ring 14 or between the gland packing 17 and the rod 3a, thereby increasing the frictional force and finally “galling”. ”And the stem 18 may not move completely. In addition, even if “galling” does not occur, the stem 18 may self-excited and the fluid may not be controlled. In such a case, it is not easy to elucidate what causes the self-excited vibration. One factor that makes it difficult to elucidate the cause of the failure is that actual operation data of the air-driven valve 1 at the time of abnormal operation is not obtained.

  In addition, if the gland packing 17 is deteriorated and hardened and loses its elasticity, the frictional resistance increases and looseness gradually occurs between the rod 3a and the gland packing 17, so that maintenance personnel regularly check the condition of the gland packing 17. It was necessary to check the above and visually check for fluid leakage. Even in such a case, if the magnitude of the sliding resistance of the gland packing 17 is known, it is possible to roughly determine whether or not fluid leakage is likely to occur. Therefore, it is important and significant to grasp the thrust operation data of the stem 18.

  Here, the air drive valve 1 is not limited to the control valve provided with the positioner 5 as described above, and even an ordinary ball valve has a feature that the drive frequency is higher than that of the electric drive valve. For example, if a period of 24 hours a day is monitored, the valve is not operated once, and is operated at least several times. Furthermore, the air-driven valve 1 used in a power plant or the like has a characteristic that a certain periodicity exists in the operation pattern. For example, when examining every week or every day, it can be seen that the vehicle is repeatedly operated with substantially the same operation pattern. Therefore, for the purpose of determining whether or not the performance of the air driven valve 1 is ensured, the necessity of constantly monitoring the operating state of the air driven valve 1 is not necessarily high.

  In view of the characteristics of the operation pattern of the air-driven valve 1 as described above, the present invention intends to reliably record and grasp abnormal data while intermittently monitoring the operation status of the air-driven valve 1. Moreover, even if a failure occurs in the air-driven valve 1 unfortunately, an on-site monitoring device for the air-driven valve 1 that can easily identify the cause of the failure from the recorded operation data is realized. This will be specifically described below.

  FIG. 2 is a block diagram showing the overall configuration of the on-site monitoring device for the air driven valve 1 according to the present invention. This on-site monitoring apparatus includes a setting unit 31, a recording unit 32, a monitoring unit 33, and a sensor 34 attached to the air driven valve 1. The setting means 31 includes setting devices for setting a monitoring interval 35, a monitoring period 36, a trigger value 37, an alarm value 38, a shift amount 39, and an excess count 40. Here, the monitoring interval 35 is a period for intermittently monitoring operation data, the monitoring period 36 is a monitoring period within one period for intermittently monitoring data, and a trigger value 37 is for recording monitored data. The alarm value 38 is the alarm value in the operation data, the shift amount 39 is the change amount of the alarm value 38, and the excess number 40 is the alarm value 38 within the monitoring period 36. Or the number of times the alarm value 38 after the shift is exceeded. The recording means 32 is composed of an EEPROM which is a non-volatile semiconductor memory, and records data of sensor output signal values. The sensor 34 includes a strain sensor 34a mounted on the side of the yoke of the valve, a temperature sensor 34b that detects the temperature of the valve, and an opening sensor 34c that detects the opening of the valve. Various types of sensors 34a to 34c are mounted. The output signals of the sensors 34a to 34c are connected to the input terminal of the monitoring means 33. Here, the reason why the strain sensor 34a is attached to the yoke of the valve is to detect the amount of thrust acting on the stem 18 of the valve. The temperature sensor 34b is attached to the valve because the valve load varies depending on the valve temperature. Furthermore, the opening degree sensor 34c is mounted because the valve load varies depending on the valve opening degree.

  FIG. 3 is a block diagram showing the configuration of the monitoring means 33. The monitoring unit 33 includes a control circuit 41 including a CPU, a nonvolatile memory 42, a PIO 44 including an A / D converter 43, a display unit 45, a communication unit 46, and a battery 47. These components are connected by a bus line 48. The battery 47 supplies power necessary for driving the control circuit 41 and the like. The output signal of the sensor 34 attached to the air driven valve 1 is connected to the bus line 48 via the A / D converter 43 and the PIO 44. Setting data from a setting device as the setting means 31 is recorded in the nonvolatile memory 42 via the control circuit 41. The display means 45 displays whether or not operation data is recorded, and specifically comprises an LED. The communication means 46 is for sending out the recorded operation data when the operation data is recorded in the nonvolatile memory 42.

  Next, the operation of the on-site monitoring apparatus 50 having the above-described configuration will be described with reference to FIGS. In FIG. 4, the horizontal axis represents time, and for example, the time for about two months is displayed. The vertical axis represents the signal output of the sensor 34 attached to the valve. For example, in the case of the strain sensor 34a attached to the yoke, the thrust amount is displayed. 5 to 7 described later, the physical meanings of the horizontal axis and the vertical axis are the same. That is, the horizontal axis represents time, and the vertical axis represents the signal output of the sensor 34 attached to the valve.

One feature of the present invention is that the operation pattern of the air-driven valve 1 has periodicity, and the period t ₁ during which the signal of the sensor 34 is monitored on the time axis is a period during which the signal of the sensor 34 is not monitored. Compared to t ₂ is that there is a very short period of time. For example, if the operation pattern of the air-driven valve 1 is periodic every day, if it is relatively new, several years after the start of operation, the period of only one day in one month is monitored, and the remaining The reliability of the valve is ensured without monitoring for 29 days or 30 days. In machinery such as valves, it is rare that a sudden failure occurs without any sign except in the case of natural disasters. In failure modes due to aging of machinery, deterioration progresses over time, so some signs appear before a serious failure that causes loss of function occurs. In the case of the air-driven valve 1, a sign appears that the sliding amount of the stem 18 increases or decreases the amount of thrust of the stem 18. Therefore, if the output data of the sensor 34 is in a good condition such that the trigger level does not exceed the trigger level once in the monitoring period t ₁ , for example, 24 hours a day, a good driving state is maintained on the next day and the next day. It is expected to be possible. When such a favorable operating state is expected, the reliability of the valve is sufficiently ensured by monitoring the operation data for only one day in one month. Such if set longer monitoring interval t ₂ of the operational data, data can be save power consumption of the battery 47 by shortening the time period t ₁ to monitor. That constantly supplies power only to the portion of the timer circuit of control circuit, the large CPU of the power consumption so as to supply power only to the monitoring period t _1, a time period that does not monitor the operation data monitoring interval t Set ₂ to sleep. This can reduce battery power consumption.

Further, in the monitoring period t in ₁ intermittently monitored by the influence of disturbance such as when there is a signal that exceeds the trigger level, accidental signal may sometimes exceed the trigger level. However, such an accidental signal does not appear continuously many times, and based on empirical knowledge, the safety of the air-driven valve 1 is sufficient if it is equal to or less than the predetermined excess number N. Secured. Thus also set longer monitoring interval t ₂ of the operating data when such data is possible to save power consumption of the battery to shorten the period t ₁ to monitor. Specifically, the intermittent monitoring described above can be realized by setting the monitoring interval t ₂ and the monitoring period t ₁ with a setting device.

FIG. 5 shows a state in which the number of sensor outputs exceeding the trigger level is a predetermined number N or more. It shows a case where the number n of sensor outputs exceeding the trigger level in the monitoring period t ₁ exceeds a preset excess number N. In this case, the signal level of the sensor output is surely increased, which means that a state requiring attention in driving is reached. On the other hand, the trigger level is set to a low value in anticipation of sufficient safety, and even if the trigger level is exceeded, it does not immediately impede driving. Therefore, in this case, the value of the sensor output is recorded, and the low trigger level is shifted to a high value to automatically shift to the trigger level 2. The trigger level 2 is set to be lower than the alarm level, which is a dangerous level, and higher than the trigger level.

  FIG. 6 shows a state after the trigger level has shifted to the trigger level 2. In this state, the sensor output value is not recorded even when the trigger level excess count of the sensor output signal level is N or more. After the trigger level has shifted to the trigger level 2, the signal level of the sensor output is below the trigger level 2, or the number of times that the signal level of the sensor output exceeds the trigger level 2 is set to a predetermined number N or less. In some cases, the sensor output value is not recorded. The sensor output value is recorded when the trigger level 2 to which the sensor output value is shifted becomes N or more a predetermined number of times. As a result, the trigger level is automatically shifted while continuing the operation of the air driven valve 1 even when the operation data of the air driven valve 1 exceeds a predetermined trigger value. By setting the value to a low value, it is possible to grasp the change over time in the operation data.

When the number of times that the sensor output value exceeds the trigger level 2 within the monitoring period t ₁ exceeds the predetermined number N, the probability that an abnormality occurs in the air driven valve 1 is relatively increased. Become. Therefore, it is necessary to strengthen the monitoring system.

FIG. 7 shows an example when the monitoring system is strengthened. In FIGS. 4 to 6 described above, the monitoring period t ₁ and the monitoring interval t ₂ for monitoring the operating data has been a constant value. In the embodiment described above, the monitoring period t _{1 is set} to 24 hours a day, and the non-monitoring period t _{2 is set} to 29 days or 30 days. When the signal level of the sensor output is stable at a low value, the safety of the air-driven valve 1 can be sufficiently ensured with a monitoring period of one month. However, as the signal level of the sensor output increases as shown in FIG. 6, it becomes difficult to ensure reliability in a monitoring system with a one-month cycle. Therefore, for example, the monitoring cycle is set to one month to half a month, and monitoring is performed twice in one month. In FIG. 7, the monitoring system is strengthened by setting the monitoring period t ₁ to 1 day and the non-monitoring period, that is, the monitoring interval t ₂ to 14 days. Either what extent the monitoring interval t ₂ can be set arbitrarily by setting means. And if the signal values within the monitoring period t ₁ is less than the trigger level 2, if it exceeds the trigger level 2 is less than the predetermined number N, the value of the sensor output is not recorded. The value of the sensor output only when the value of the sensor output exceeding the trigger level 2 in the monitoring period t ₁ exceeds a predetermined number N is set to be recorded. Thus, since the trigger value sensor output is predetermined it can be monitored by shortening the monitoring interval t ₂ After exceeds a predetermined number N in the predetermined time period t _1, thereby improving the probability of capture of the abnormal data air driven valve 1 . Further, it is possible to monitor the state in detail corresponding to the operating conditions of the air driven valve 1.

  FIG. 8 shows an actual application example of the field monitoring apparatus 50 according to the present invention. It goes without saying that one air-driven valve 1 can be monitored for one monitoring device, but as shown in FIG. It is possible to monitor the operating state of the air driven valve 1 of the table. By adopting such a configuration, an on-site monitoring device 50 with excellent economy can be realized.

  As mentioned above, although this invention was demonstrated based on the Example, this invention can carry out various deformation | transformation implementation. For example, in the above-described embodiment, the control valve provided with the valve positioner has been described. However, it goes without saying that the present invention can also be applied to the air-driven valve 1 using an ordinary ball valve without the valve positioner. Also. In the above embodiment, the example in which the trigger level is shifted to the trigger level 2 has been described. However, the trigger level can be shifted from the trigger level 2 to the trigger level 3 in two stages.

It is sectional drawing which shows the structure of an air drive valve. It is a block diagram which shows the whole structure of the field monitoring apparatus of the air drive valve which concerns on this invention. It is a block diagram which shows the structure of a monitoring means. It is a figure which shows an example of driving | operation data. It is a figure which shows an example of driving | operation data. It is a figure which shows an example of driving | operation data. It is a figure which shows an example of driving | operation data. It is a figure which shows the example of application of the on-site monitoring apparatus of the air drive valve which concerns on this invention.

Explanation of symbols

1 Air driven valve
18 stem
21 Diaphragm
23 Pressure chamber
32 Recording means
33 Monitoring means
34a ~ 34c sensor
50 Field monitoring equipment

Claims (4)

In an air driven valve that drives a stem fixed to a diaphragm by introducing compressed air into the pressure chamber, a sensor that detects operation data of the air driven valve attached to the valve structure member, and an output of the sensor intermittently Monitoring means for monitoring and recording means for recording the output of the sensor so that the output of the sensor is recorded when the output of the sensor exceeds a predetermined trigger value within a predetermined period of time. An on-site monitoring device for air-driven valves. In an air driven valve that drives a stem fixed to a diaphragm by introducing compressed air into the pressure chamber, a sensor that detects operation data of the air driven valve attached to the valve structure member, and an output of the sensor intermittently Monitoring means for monitoring and recording means for recording the output of the sensor, and when the output of the sensor exceeds a predetermined trigger value within a predetermined period, the trigger value is shifted, and the sensor An on-site monitoring device for an air-driven valve, wherein the output of the sensor is recorded when the output of the sensor exceeds the predetermined trigger number after the shift. In an air driven valve that drives a stem fixed to a diaphragm by introducing compressed air into a pressure chamber, a sensor that detects operation data of the air driven valve attached to the valve structure member, and an output of the sensor intermittently Monitoring means for monitoring, and recording means for recording the output of the sensor, and when the output of the sensor exceeds a predetermined trigger value within a predetermined period, the monitoring interval is shortened, and the output of the sensor When the trigger value exceeds the predetermined number of times within a predetermined period, the output of the sensor is recorded. The on-site monitoring device for an air driven valve according to any one of claims 1 to 3, wherein the sensor is a strain gauge attached to a yoke of the air driven valve.

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